It's Mario's birthday. He walks into his door and a bunch of Toads, Luigi and Peach jump out. Then Bowser lifts the roof and kidnaps the guests. Mario runs off to save them.
- Prologue: Mushroom Mayhem
- Chapter 1: Riding to Mystery Island
- Chapter 2: Mystery Crash
- Chapter 3: Dinos and Mountains and Eggs! Oh my!
- Chapter 4: Toadstool Town
- Chapter 5: Shipwrecked on Phantom Island
- Chapter 6: Shroomba Town
- Chapter 7: Koopa Kingdom
- Chapter 8: The Finale
Main Article: Paper Mario 4/Walkthrough